A justice of the peace in Ontario is a judicial officer appointed pursuant to the Justices of the Peace Act, R.S.O. 1990, C. J.4. This Act affirms that a justice of the peace has judicial jurisdiction throughout Ontario and creates a framework under which justices of the peace are appointed and hold office, and also provides for the conditions under which they perform their duties. There are over 325 justices of the peace in Ontario that are assigned to and perform judicial responsibilities. Both provincial court judges and justices of the peace compose the Ontario Court of Justice, one of Ontario’s two trial courts.

The judicial functions, powers and duties of a justice of the peace are set out in legislation and case law. Two of the more important legislative Acts which confer jurisdiction upon a justice of the peace are the Criminal Code and the Ontario Provincial Offences Act, but there are many other federal and provincial statutes and regulations that empower justices of the peace with legal authority and/or jurisdiction. Primarily, the two main areas of jurisdiction are criminal law and regulatory law (provincial offences).

Respecting criminal law, justices of the peace preside over virtually all judicial interim release (bail) hearings in the province and the majority of criminal remand courts. They also preside over other criminal hearings. They receive informations (the document which commences a criminal proceeding), confirm or consider the issuance of process by either a summons or a warrant and are responsible for receiving and considering the denial or issuance of search warrants and other matters of criminal process.

Justices of the peace exercise jurisdiction over the majority of provincial regulatory offences and municipal by-law prosecutions. As in criminal proceedings, justices of the peace receive informations and warrant applications, consider the issuance of process and preside at hearings and trials.

On appointment, a justice of the peace must cease other employment and refrain from any political activity. The Justices of the Peace Act states that a justice of the peace shall not engage in any other remunerative work without the approval of the Justices of the Peace Review Council.

Justices of the peace in Ontario must retire upon attaining the age of 65 years but may continue in office until attaining the age of 75 years, subject to the annual approval of the Chief Justice of the Ontario Court of Justice.